The English globe being a stabil and immobil one, performing what the ordinary globes do, and much more / invented and described by the Right Honorable, the Earl of Castlemaine ; and now publish't by Joseph Moxon ...

OPERATION III. How by the help of your Globe to measure any Tower or height, and yet not▪ to seem to use any Instrument in the Operation.

THIS Operation may perchance a little surprise some, and yet it differs not in reality from the former; that showing you how to measure a height by your Globe upon the place, and this how to do it privately. To perform then the Operation, you must choose (when you are alone) any of the aforesaid Numbers, on the Quadrant of Proportion, as suppose 25, and seeing that belongs to the 14th. Degree from the Zenith, recti∣fy your Bead to the Complement, i. e. to the 76th from the Zenith in the said Quadrant; this being done move your String hanging on the Zenith's Pin, till your Bead touches the Parallel of the Day, which we now suppose to be the tenth of May, and the Hour-Circle, that meets with it there (to wit that of six in the morning, or six in the afternoon) tells you that at those hours, on that day of the Month, the perpendicular will be the fourth part of the Shade, i. e. as twenty five to an hun∣dred, so that having discours'd with some body of the possibili∣ty

of measuring heights without an Instrument, repair with him to any convenient place, about the foresaid times of the day, and when you find by your Watch that 'tis exactly six, do but measure the Shade and you will have the required height. And by the way take notice, that as it is in your power to choose what proportion you please, and the more odd and exotic it happens (if you can quickly reduce it) the better it is, for then People will not perchance so soon comprehend the Operation; I say, as you can choose your Proportion, so you may choose the Hour also, for if your Bead be rectify'd to the chosen Propor∣tion, according to the foregoing Example and Instructions, and brought to the hour pitcht upon (suppose 3 in the afternoon) the Parallel, (to wit, that of the fifth of February,) which meets with the the said Bead and Hour-Circle, tells you that then the Proportion will thus happen; nay, you may choose what day and hour you please, if you will be content with the casual Proportion or number which the Bead, when rectify'd (as we mentioned) falls upon.